Surgeon volume as an indicator of outcomes after carotid endarterectomy: An effect independent of specialty practice and hospital volume

Cowan, John A; Dimick, Justin B; Thompson, B.Gregory; Stanley, James C; Upchurch, Gilbert R

« Previous Next »Journal of the American College of Surgeons
Volume 195, Issue 6 , Pages 814-821, December 2002

Surgeon volume as an indicator of outcomes after carotid endarterectomy:☆

An effect independent of specialty practice and hospital volume

This work was presented at the 63^rd Annual Meeting of the Society of University Surgeons, Residents’ Forum, Honolulu, HI, February 2002.

John A Cowan Jr, MD
- Department of Neurosurgery (Cowan, Thompson), University of Michigan Medical Center, Ann Arbor, MI, USA
Justin B Dimick, MD
- Department of Surgery (Dimick, Stanley, Upchurch), University of Michigan Medical Center, Ann Arbor, MI, USA
B.Gregory Thompson, MD
- Department of Neurosurgery (Cowan, Thompson), University of Michigan Medical Center, Ann Arbor, MI, USA
James C Stanley, MD, FACS
- Department of Surgery (Dimick, Stanley, Upchurch), University of Michigan Medical Center, Ann Arbor, MI, USA
Gilbert R Upchurch Jr, MD, FACS
- Department of Surgery (Dimick, Stanley, Upchurch), University of Michigan Medical Center, Ann Arbor, MI, USA
- Correspondence address: Gilbert R Upchurch Jr, MD, 1500 East Medical Center Dr, Taubman Center 2210, Ann Arbor, MI 48109-0329, USA.

Received 20 March 2002; received in revised form 10 July 2002; accepted 15 July 2002.

Abstract

Background

High-volume hospitals have been shown to have superior outcomes after carotid endarterectomy (CEA), but the contribution of surgeon volume and specialty practice to CEA outcomes in a national sample is unknown.

Study design

Using the National Inpatient Sample for 1996 and 1997, 35,821 patients who underwent CEA (ICD-9-CM code 3812) and had data for unique surgeon identification were studied. Surgeons were categorized in terms of annual CEA volume as low-volume surgeons (< 10 procedures), medium-volume surgeons (10 to 29), and high-volume surgeons (≥ 30). Data from cardiac, general, neurologic, and vascular surgical practices were analyzed. In-hospital mortality, postoperative stroke, and prolonged length of stay (> 4 days) were the primary outcomes variables. Unadjusted and case-mix adjusted analyses were performed.

Results

The overall in-hospital mortality was 0.61%. CEA was performed annually by high-volume surgeons in 52% of patients, by medium-volume surgeons in 30% of patients, and by low-volume surgeons in 18% of patients. Observed mortality by surgeon volume was 0.44% for high-volume surgeons, 0.63% for medium-volume surgeons, and 1.1% for low-volume surgeons (p < 0.001). The postoperative stroke rate was 1.14% for high-volume surgeons, 1.63% for medium-volume surgeons, and 2.03% for low-volume surgeons (p < 0.001). Surgeon specialty had no statistically significant effect on mortality or postoperative stroke. In the logistic regression model, increased risk of mortality was associated with emergent admission (odds ratio [OR] = 2.1; 95% confidence interval [CI] 1.6 to 2.8, p < 0.001), patient age > 65 years (OR = 2.0; 95% CI 1.3 to 3.1, p = 0.001), low-volume surgeon (OR = 1.9; 95% CI 1.4 to 2.5, p < 0.001), and COPD (OR = 1.8; 95% CI 1.3 to 2.5, p = 0.001). Low hospital CEA volume (< 100) was not a significant risk factor in the multivariate analysis.

Conclusions

More than 50% of the CEAs in the United States are performed by high-volume surgeons with superior outcomes. Health policy efforts should focus on reducing the number of low-volume surgeons, regardless of surgeon specialty or total hospital CEA volume.